20681816 has 32 divisors (see below), whose sum is σ = 40260240. Its totient is φ = 9952128.

The previous prime is 20681813. The next prime is 20681821. The reversal of 20681816 is 61818602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20681813) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31346 + ... + 31998.

Almost surely, 2^20681816 is an apocalyptic number.

It is an amenable number.

20681816 is a deficient number, since it is larger than the sum of its proper divisors (19578424).

20681816 is a wasteful number, since it uses less digits than its factorization.

20681816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 803 (or 799 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 20681816 is about 4547.7264649493. The cubic root of 20681816 is about 274.4919147411.

The spelling of 20681816 in words is "twenty million, six hundred eighty-one thousand, eight hundred sixteen".